3D Printers to Build NASA's Spare Parts & Rocket Engines

Charles Bolden, NASA administrator and former astronaut, praises the potential of 3D printing to one day quickly create any parts that space travelers would need, and do it with material from whatever planet, moon, or asteroid they happen to inhabit.

In his recent State of the Union address, President Obama spoke glowingly of 3D printing, saying the technology "has the potential to revolutionize the way we make almost everything." At NASA, the revolution is already under way. Engineers are now testing 3D printing (more broadly known as additive manufacturing) for making engine parts for the Space Launch System (SLS), the vehicle slated to take mankind back to the moon, to asteroids, and someday to Mars. A 3D printer will soon head to the International Space Station. And in the future, NASA hopes 3D printers will let astronauts fabricate tools, spare parts, or virtually anything their mission requires throughout the solar system.

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"Additive manufacturing is this new technology that really gives us an endless set of possibilities for the products we manufacture at NASA for our terrestrial launch vehicle and our in-space applications," says John Vickers, assistant manager of the Materials and Processes Laboratory at NASA's Marshall Space Flight Center.

In a sign of how seriously NASA is taking the technology, on Friday agency chief Charles Bolden toured an additive manufacturing facility at Marshall. "The things going on here are very impressive," Bolden tells PM. "I was surprised by the maturity of the systems already."

Additive manufacturing consists of successively adding thin layers of material to build up an object in three dimensions based on a digital blueprint. The technology's costs have plummeted in recent years, prompting everyone from garage tinkerers to America's space agency to get in on the action. "All NASA centers have some capability in additive manufacturing or 3D printing," Vickers says.

Bolden looks ahead to when 3D printing will fundamentally redefine the planning of manned spaceflight missions. "My chief technologist Mason Peck and I talk every week," Bolden says. "He envisions somewhere down the road we'll launch with nothing except an additive manufacturing set of machines or apparatus; everything we need we'll produce when we get there. It could be incredible."

NASA is beginning with smaller steps. Ames Research Center in California is working on small satellite development, for example, while Florida's Kennedy Space Center has eyes on using lunar, martian, and asteroid regolith as raw material for 3D printers. At Marshall, where Vickers works, the focus is on propulsion systems. Engineers are experimenting with a process called selective laser melting (SLM) to build complex, conventionally hard-to-make components for the SLS engines, called the RS-25 and J-2X. In the SLM machine's chamber, lasers melt and fuse a finely powdered substance—in this case an aeronautics-grade, nickel-based alloy called Inconel—in a designed pattern. The current machine can create objects only about a half cubic foot in volume, but larger SLM devices could go on to make bigger and bigger engine components. "We believe it will be possible in the future to build all of the hard parts we would desire to build out of additive technology," Vickers says.

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The same factors that are pushing more and more entrepreneurs to embrace 3D printing—lower cost and shorter production times—are enticing NASA too. As an example, Vickers says, an engine injector made with conventional fabrication techniques of molding and welding might cost in the range of $250,000. "We hope to reduce that by a factor of 10 and get in the range of $25,000," Vickers says. "That's huge when you start talking about reducing the cost." Production times could also dwindle from six months to just weeks.

A conventional injector design could contain some 300 parts, Vickers adds, but the additive manufacturing could build it all as a single unit. That means the production could be not only faster and cheaper, but also safer; it cuts down on the number of individual aeronautical parts that could have manufacturing defects, as well as the time needed for rigorous inspections to root out such flaws.

Another benefit: SLM components will not need to be welded together. "Generally, welds are a weak point," Vickers says. "So the elimination of welds is inherently a good thing." NASA will test the new components to see how they stand up against intense heat and vibrations. One component made via SLM under study and that Vickers talked to Bolden about on his tour is called a POGO Z-baffle, which dampens vertical oscillations in an oxygen line in the RS-25 rocket engine. The plan is to certify the part for use on the maiden SLS flight in 2017, Vickers says.

Putting additive manufacturing right at astronauts' fingertips is also in the works. In October 2014 a SpaceX flight is scheduled to deliver a 3D printer for fashioning plastic objects to the International Space Station. The NASA effort is a collaboration with startup company Made In Space. Should the technology prove successful on the ISS, Bolden says it could be transitioned to the SLS's manned Orion space capsule and other spacecraft.

Bolden piloted or commanded four shuttle missions from 1986 to 1994, including the mission that deployed the Hubble Space Telescope in 1990. He recalls a situation on his last mission aboard space shuttle Discovery where a 3D printer could have come in handy. Crew member Franklin Chang-Diaz was setting up a SPACEHAB module, which sat in a space shuttle's payload bay and provided astronauts a safe, pressurized environment where they could work without wearing a spacesuit. "Franklin noticed that the air duct into the SPACEHAB module that provided life support had been crushed," Bolden says. "We were worried about it, as were people on the ground." To prevent the flimsy duct from closing off completely, Bolden says the astronauts devised a solution: taking the hard plastic cover from an atlas, rolling it up, and then sticking it inside the duct. But a 3D printer might have saved considerable worry and the need to resort to jury-rigging while in orbit. "If we had this capacity with us then," Bolden says, "we could have ordered up the second module component we needed and printed one out that was plastic that wasn't able to be crushed."

This is this sort of ad hoc versatility that excites interplanetary mission planners. Should a spacecraft part break down or need replacement, astronauts could simply type into a 3D printer what component they need. Want a stronger shovel to dig a hole on Mars? An astronaut-engineer could create custom tools on the fly. 3D-printed objects themselves could be recycled as feedstock for the next set of wares.

"The further you get from Earth, the harder it is to take all the supplies and redundant parts you might need," Vickers says. "This capability to produce parts in space is a critical enabling tech for exploring if we're really ever going to spend long periods of time on other planets or the moon."

"A mission to Mars today is eight months," Bolden says. "There's no sending back asking for UPS or FedEx."